CT Predictors of Epicardial Coronary Spasm in Patients With Angina and Nonobstructive Coronary Arteries

BACKGROUND: Recent studies have shown that vasospastic angina (VSA) is associated with myocardial bridge (MB) and pericoronary adipose tissue inflammation. We aimed to investigate the clinical and coronary computed tomography angiographic (CCTA) features that could predict VSA in patients with angina and nonobstructive coronary arteries. METHODS: We retrospectively studied patients with angina and nonobstructive coronary arteries who underwent a spasm provocation test and CCTA within 3 months before the spasm provocation test. Pericoronary adipose tissue inflammation was evaluated using the fat attenuation index (FAI) of the proximal reference diameter and the inner 2 mm adipose tissue layer (FAI 2mm ) from the vessel wall. Coronary plaques were qualitatively classified as noncalcified or calcified plaques in each vessel. In addition, MB was evaluated in the left anterior descending artery. RESULTS: This study included 142 patients, with 55 (38.7%) diagnosed with VSA. Factors associated with VSA included male sex (74.5% versus 51.7%, P =0.01), smoking history (70.9% versus 52.9%, P =0.05), CCTA-defined MB (49.1% versus 28.7%, P =0.02), and FAI, especially FAI 2mm in the right coronary artery-FAI 2mm (−68.8 Hounsfield unit versus −74.0 Hounsfield unit, P <0.01), as well as the presence of CCTA-defined mixed or noncalcified plaque anywhere in the coronary tree (65.5% versus 39.1%, P <0.01). In a multivariable analysis, CCTA-defined MB (odds ratio, 2.23 [95% CI, 1.03–4.83]; P =0.04), right coronary artery-FAI 2mm (odds ratio, 1.07 [95% CI, 1.02–1.12]; P <0.01), and the presence of mixed or noncalcified plaque (odds ratio, 3.15 [95% CI, 1.45–6.80]; P <0.01) were independently associated with VSA. A combination of CCTA-defined MB in the left descending artery, high right coronary artery-FAI 2mm (≥−72.6 Hounsfield unit, median), and CCTA-defined mixed or noncalcified plaque in the coronary tree predicted VSA with a 75.0% probability, while the absence of all 3 factors precluded VSA with 95.6% probability. CONCLUSIONS: For patients with angina and nonobstructive coronary arteries, a prespasm provocation test using a noninvasive comprehensive assessment with CCTA may help identify those at high risk for VSA.